<?php

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  exit('No direct script access allowed');
/**
 * CodeIgniter
 *
 * An open source application development framework for PHP 5.1.6 or newer
 *
 * @package		CodeIgniter
 * @author		ExpressionEngine Dev Team
 * @copyright	Copyright (c) 2008 - 2011, EllisLab, Inc.
 * @license		http://codeigniter.com/user_guide/license.html
 * @link		http://codeigniter.com
 * @since		Version 1.0
 * @filesource
 */
// ------------------------------------------------------------------------

/**
 * Session Class
 *
 * @package		CodeIgniter
 * @subpackage	Libraries
 * @category	Sessions
 * @author		ExpressionEngine Dev Team
 * @link		http://codeigniter.com/user_guide/libraries/sessions.html
 */
class CI_Session {

  var $sess_encrypt_cookie = FALSE;
  var $sess_use_database = FALSE;
  var $sess_table_name = '';
  var $sess_expiration = 7200;
  var $sess_expire_on_close = FALSE;
  var $sess_match_ip = FALSE;
  var $sess_match_useragent = TRUE;
  var $sess_cookie_name = 'ci_session';
  var $cookie_prefix = '';
  var $cookie_path = '';
  var $cookie_domain = '';
  var $cookie_secure = FALSE;
  var $sess_time_to_update = 300;
  var $encryption_key = '';
  var $flashdata_key = 'flash';
  var $time_reference = 'time';
  var $gc_probability = 5;
  var $userdata = array();
  var $CI;
  var $now;

  /**
   * Session Constructor
   *
   * The constructor runs the session routines automatically
   * whenever the class is instantiated.
   */
  public function __construct($params = array()) {
    log_message('debug', "Session Class Initialized");

    // Set the super object to a local variable for use throughout the class
    $this->CI = & get_instance();

    // Set all the session preferences, which can either be set
    // manually via the $params array above or via the config file
    foreach (array('sess_encrypt_cookie', 'sess_use_database', 'sess_table_name', 'sess_expiration', 'sess_expire_on_close', 'sess_match_ip', 'sess_match_useragent', 'sess_cookie_name', 'cookie_path', 'cookie_domain', 'cookie_secure', 'sess_time_to_update', 'time_reference', 'cookie_prefix', 'encryption_key') as $key) {
      $this->$key = (isset($params[$key])) ? $params[$key] : $this->CI->config->item($key);
    }

    if ($this->encryption_key == '') {
      show_error('In order to use the Session class you are required to set an encryption key in your config file.');
    }

    // Load the string helper so we can use the strip_slashes() function
    $this->CI->load->helper('string');

    // Do we need encryption? If so, load the encryption class
    if ($this->sess_encrypt_cookie == TRUE) {
      $this->CI->load->library('encrypt');
    }

    // Are we using a database?  If so, load it
    if ($this->sess_use_database === TRUE AND $this->sess_table_name != '') {
      $this->CI->load->database();
    }

    // Set the "now" time.  Can either be GMT or server time, based on the
    // config prefs.  We use this to set the "last activity" time
    $this->now = $this->_get_time();

    // Set the session length. If the session expiration is
    // set to zero we'll set the expiration two years from now.
    if ($this->sess_expiration == 0) {
      $this->sess_expiration = (60 * 60 * 24 * 365 * 2);
    }

    // Set the cookie name
    $this->sess_cookie_name = $this->cookie_prefix . $this->sess_cookie_name;

    // Run the Session routine. If a session doesn't exist we'll
    // create a new one.  If it does, we'll update it.
    if (!$this->sess_read()) {
      $this->sess_create();
    } else {
      $this->sess_update();
    }

    // Delete 'old' flashdata (from last request)
    $this->_flashdata_sweep();

    // Mark all new flashdata as old (data will be deleted before next request)
    $this->_flashdata_mark();

    // Delete expired sessions if necessary
    $this->_sess_gc();

    log_message('debug', "Session routines successfully run");
  }

  // --------------------------------------------------------------------

  /**
   * Fetch the current session data if it exists
   *
   * @access	public
   * @return	bool
   */
  function sess_read() {
    // Fetch the cookie
    $session = $this->CI->input->cookie($this->sess_cookie_name);

    // No cookie?  Goodbye cruel world!...
    if ($session === FALSE) {
      log_message('debug', 'A session cookie was not found.');
      return FALSE;
    }

    // Decrypt the cookie data
    if ($this->sess_encrypt_cookie == TRUE) {
      $session = $this->CI->encrypt->decode($session);
    } else {
      // encryption was not used, so we need to check the md5 hash
      $hash = substr($session, strlen($session) - 32); // get last 32 chars
      $session = substr($session, 0, strlen($session) - 32);

      // Does the md5 hash match?  This is to prevent manipulation of session data in userspace
      if ($hash !== md5($session . $this->encryption_key)) {
        log_message('error', 'The session cookie data did not match what was expected. This could be a possible hacking attempt.');
        $this->sess_destroy();
        return FALSE;
      }
    }

    // Unserialize the session array
    $session = $this->_unserialize($session);

    // Is the session data we unserialized an array with the correct format?
    if (!is_array($session) OR ! isset($session['session_id']) OR ! isset($session['ip_address']) OR ! isset($session['user_agent']) OR ! isset($session['last_activity'])) {
      $this->sess_destroy();
      return FALSE;
    }

    // Is the session current?
    if (($session['last_activity'] + $this->sess_expiration) < $this->now) {
      $this->sess_destroy();
      return FALSE;
    }

    // Does the IP Match?
    if ($this->sess_match_ip == TRUE AND $session['ip_address'] != $this->CI->input->ip_address()) {
      $this->sess_destroy();
      return FALSE;
    }

    // Does the User Agent Match?
    if ($this->sess_match_useragent == TRUE AND trim($session['user_agent']) != trim(substr($this->CI->input->user_agent(), 0, 120))) {
      $this->sess_destroy();
      return FALSE;
    }

    // Is there a corresponding session in the DB?
    if ($this->sess_use_database === TRUE) {
      $this->CI->db->where('session_id', $session['session_id']);

      if ($this->sess_match_ip == TRUE) {
        $this->CI->db->where('ip_address', $session['ip_address']);
      }

      if ($this->sess_match_useragent == TRUE) {
        $this->CI->db->where('user_agent', $session['user_agent']);
      }

      $query = $this->CI->db->get($this->sess_table_name);

      // No result?  Kill it!
      if ($query->num_rows() == 0) {
        $this->sess_destroy();
        return FALSE;
      }

      // Is there custom data?  If so, add it to the main session array
      $row = $query->row();
      if (isset($row->user_data) AND $row->user_data != '') {
        $custom_data = $this->_unserialize($row->user_data);

        if (is_array($custom_data)) {
          foreach ($custom_data as $key => $val) {
            $session[$key] = $val;
          }
        }
      }
    }

    // Session is valid!
    $this->userdata = $session;
    unset($session);

    return TRUE;
  }

  // --------------------------------------------------------------------

  /**
   * Write the session data
   *
   * @access	public
   * @return	void
   */
  function sess_write() {
    // Are we saving custom data to the DB?  If not, all we do is update the cookie
    if ($this->sess_use_database === FALSE) {
      $this->_set_cookie();
      return;
    }

    // set the custom userdata, the session data we will set in a second
    $custom_userdata = $this->userdata;
    $cookie_userdata = array();

    // Before continuing, we need to determine if there is any custom data to deal with.
    // Let's determine this by removing the default indexes to see if there's anything left in the array
    // and set the session data while we're at it
    foreach (array('session_id', 'ip_address', 'user_agent', 'last_activity') as $val) {
      unset($custom_userdata[$val]);
      $cookie_userdata[$val] = $this->userdata[$val];
    }

    // Did we find any custom data?  If not, we turn the empty array into a string
    // since there's no reason to serialize and store an empty array in the DB
    if (count($custom_userdata) === 0) {
      $custom_userdata = '';
    } else {
      // Serialize the custom data array so we can store it
      $custom_userdata = $this->_serialize($custom_userdata);
    }

    // Run the update query
    $this->CI->db->where('session_id', $this->userdata['session_id']);
    $this->CI->db->update($this->sess_table_name, array('last_activity' => $this->userdata['last_activity'], 'user_data' => $custom_userdata));

    // Write the cookie.  Notice that we manually pass the cookie data array to the
    // _set_cookie() function. Normally that function will store $this->userdata, but
    // in this case that array contains custom data, which we do not want in the cookie.
    $this->_set_cookie($cookie_userdata);
  }

  // --------------------------------------------------------------------

  /**
   * Create a new session
   *
   * @access	public
   * @return	void
   */
  function sess_create() {
    $sessid = '';
    while (strlen($sessid) < 32) {
      $sessid .= mt_rand(0, mt_getrandmax());
    }

    // To make the session ID even more secure we'll combine it with the user's IP
    $sessid .= $this->CI->input->ip_address();

    $this->userdata = array(
        'session_id' => md5(uniqid($sessid, TRUE)),
        'ip_address' => $this->CI->input->ip_address(),
        'user_agent' => substr($this->CI->input->user_agent(), 0, 120),
        'last_activity' => $this->now,
        'user_data' => ''
    );


    // Save the data to the DB if needed
    if ($this->sess_use_database === TRUE) {
      $this->CI->db->query($this->CI->db->insert_string($this->sess_table_name, $this->userdata));
    }

    // Write the cookie
    $this->_set_cookie();
  }

  // --------------------------------------------------------------------

  /**
   * Update an existing session
   *
   * @access	public
   * @return	void
   */
  function sess_update() {
    // We only update the session every five minutes by default
    if (($this->userdata['last_activity'] + $this->sess_time_to_update) >= $this->now) {
      return;
    }

    // Save the old session id so we know which record to
    // update in the database if we need it
    $old_sessid = $this->userdata['session_id'];
    $new_sessid = '';
    while (strlen($new_sessid) < 32) {
      $new_sessid .= mt_rand(0, mt_getrandmax());
    }

    // To make the session ID even more secure we'll combine it with the user's IP
    $new_sessid .= $this->CI->input->ip_address();

    // Turn it into a hash
    $new_sessid = md5(uniqid($new_sessid, TRUE));

    // Update the session data in the session data array
    $this->userdata['session_id'] = $new_sessid;
    $this->userdata['last_activity'] = $this->now;

    // _set_cookie() will handle this for us if we aren't using database sessions
    // by pushing all userdata to the cookie.
    $cookie_data = NULL;

    // Update the session ID and last_activity field in the DB if needed
    if ($this->sess_use_database === TRUE) {
      // set cookie explicitly to only have our session data
      $cookie_data = array();
      foreach (array('session_id', 'ip_address', 'user_agent', 'last_activity') as $val) {
        $cookie_data[$val] = $this->userdata[$val];
      }

      $this->CI->db->query($this->CI->db->update_string($this->sess_table_name, array('last_activity' => $this->now, 'session_id' => $new_sessid), array('session_id' => $old_sessid)));
    }

    // Write the cookie
    $this->_set_cookie($cookie_data);
  }

  // --------------------------------------------------------------------

  /**
   * Destroy the current session
   *
   * @access	public
   * @return	void
   */
  function sess_destroy() {
    // Kill the session DB row
    if ($this->sess_use_database === TRUE && isset($this->userdata['session_id'])) {
      $this->CI->db->where('session_id', $this->userdata['session_id']);
      $this->CI->db->delete($this->sess_table_name);
    }

    // Kill the cookie
    setcookie(
            $this->sess_cookie_name, addslashes(serialize(array())), ($this->now - 31500000), $this->cookie_path, $this->cookie_domain, 0
    );

    // Kill session data
    $this->userdata = array();
  }

  // --------------------------------------------------------------------

  /**
   * Fetch a specific item from the session array
   *
   * @access	public
   * @param	string
   * @return	string
   */
  function userdata($item) {
    return (!isset($this->userdata[$item])) ? FALSE : $this->userdata[$item];
  }

  // --------------------------------------------------------------------

  /**
   * Fetch all session data
   *
   * @access	public
   * @return	array
   */
  function all_userdata() {
    return $this->userdata;
  }

  // --------------------------------------------------------------------

  /**
   * Add or change data in the "userdata" array
   *
   * @access	public
   * @param	mixed
   * @param	string
   * @return	void
   */
  function set_userdata($newdata = array(), $newval = '') {
    if (is_string($newdata)) {
      $newdata = array($newdata => $newval);
    }

    if (count($newdata) > 0) {
      foreach ($newdata as $key => $val) {
        $this->userdata[$key] = $val;
      }
    }

    $this->sess_write();
  }

  // --------------------------------------------------------------------

  /**
   * Delete a session variable from the "userdata" array
   *
   * @access	array
   * @return	void
   */
  function unset_userdata($newdata = array()) {
    if (is_string($newdata)) {
      $newdata = array($newdata => '');
    }

    if (count($newdata) > 0) {
      foreach ($newdata as $key => $val) {
        unset($this->userdata[$key]);
      }
    }

    $this->sess_write();
  }

  // ------------------------------------------------------------------------

  /**
   * Add or change flashdata, only available
   * until the next request
   *
   * @access	public
   * @param	mixed
   * @param	string
   * @return	void
   */
  function set_flashdata($newdata = array(), $newval = '') {
    if (is_string($newdata)) {
      $newdata = array($newdata => $newval);
    }

    if (count($newdata) > 0) {
      foreach ($newdata as $key => $val) {
        $flashdata_key = $this->flashdata_key . ':new:' . $key;
        $this->set_userdata($flashdata_key, $val);
      }
    }
  }

  // ------------------------------------------------------------------------

  /**
   * Keeps existing flashdata available to next request.
   *
   * @access	public
   * @param	string
   * @return	void
   */
  function keep_flashdata($key) {
    // 'old' flashdata gets removed.  Here we mark all
    // flashdata as 'new' to preserve it from _flashdata_sweep()
    // Note the function will return FALSE if the $key
    // provided cannot be found
    $old_flashdata_key = $this->flashdata_key . ':old:' . $key;
    $value = $this->userdata($old_flashdata_key);

    $new_flashdata_key = $this->flashdata_key . ':new:' . $key;
    $this->set_userdata($new_flashdata_key, $value);
  }

  // ------------------------------------------------------------------------

  /**
   * Fetch a specific flashdata item from the session array
   *
   * @access	public
   * @param	string
   * @return	string
   */
  function flashdata($key) {
    $flashdata_key = $this->flashdata_key . ':old:' . $key;
    return $this->userdata($flashdata_key);
  }

  // ------------------------------------------------------------------------

  /**
   * Identifies flashdata as 'old' for removal
   * when _flashdata_sweep() runs.
   *
   * @access	private
   * @return	void
   */
  function _flashdata_mark() {
    $userdata = $this->all_userdata();
    foreach ($userdata as $name => $value) {
      $parts = explode(':new:', $name);
      if (is_array($parts) && count($parts) === 2) {
        $new_name = $this->flashdata_key . ':old:' . $parts[1];
        $this->set_userdata($new_name, $value);
        $this->unset_userdata($name);
      }
    }
  }

  // ------------------------------------------------------------------------

  /**
   * Removes all flashdata marked as 'old'
   *
   * @access	private
   * @return	void
   */
  function _flashdata_sweep() {
    $userdata = $this->all_userdata();
    foreach ($userdata as $key => $value) {
      if (strpos($key, ':old:')) {
        $this->unset_userdata($key);
      }
    }
  }

  // --------------------------------------------------------------------

  /**
   * Get the "now" time
   *
   * @access	private
   * @return	string
   */
  function _get_time() {
    if (strtolower($this->time_reference) == 'gmt') {
      $now = time();
      $time = mktime(gmdate("H", $now), gmdate("i", $now), gmdate("s", $now), gmdate("m", $now), gmdate("d", $now), gmdate("Y", $now));
    } else {
      $time = time();
    }

    return $time;
  }

  // --------------------------------------------------------------------

  /**
   * Write the session cookie
   *
   * @access	public
   * @return	void
   */
  function _set_cookie($cookie_data = NULL) {
    if (is_null($cookie_data)) {
      $cookie_data = $this->userdata;
    }

    // Serialize the userdata for the cookie
    $cookie_data = $this->_serialize($cookie_data);

    if ($this->sess_encrypt_cookie == TRUE) {
      $cookie_data = $this->CI->encrypt->encode($cookie_data);
    } else {
      // if encryption is not used, we provide an md5 hash to prevent userside tampering
      $cookie_data = $cookie_data . md5($cookie_data . $this->encryption_key);
    }

    $expire = ($this->sess_expire_on_close === TRUE) ? 0 : $this->sess_expiration + time();

    // Set the cookie
    setcookie(
            $this->sess_cookie_name, $cookie_data, $expire, $this->cookie_path, $this->cookie_domain, $this->cookie_secure
    );
  }

  // --------------------------------------------------------------------

  /**
   * Serialize an array
   *
   * This function first converts any slashes found in the array to a temporary
   * marker, so when it gets unserialized the slashes will be preserved
   *
   * @access	private
   * @param	array
   * @return	string
   */
  function _serialize($data) {
    if (is_array($data)) {
      foreach ($data as $key => $val) {
        if (is_string($val)) {
          $data[$key] = str_replace('\\', '{{slash}}', $val);
        }
      }
    } else {
      if (is_string($data)) {
        $data = str_replace('\\', '{{slash}}', $data);
      }
    }

    return serialize($data);
  }

  // --------------------------------------------------------------------

  /**
   * Unserialize
   *
   * This function unserializes a data string, then converts any
   * temporary slash markers back to actual slashes
   *
   * @access	private
   * @param	array
   * @return	string
   */
  function _unserialize($data) {
    $data = @unserialize(strip_slashes($data));

    if (is_array($data)) {
      foreach ($data as $key => $val) {
        if (is_string($val)) {
          $data[$key] = str_replace('{{slash}}', '\\', $val);
        }
      }

      return $data;
    }

    return (is_string($data)) ? str_replace('{{slash}}', '\\', $data) : $data;
  }

  // --------------------------------------------------------------------

  /**
   * Garbage collection
   *
   * This deletes expired session rows from database
   * if the probability percentage is met
   *
   * @access	public
   * @return	void
   */
  function _sess_gc() {
    if ($this->sess_use_database != TRUE) {
      return;
    }

    srand(time());
    if ((rand() % 100) < $this->gc_probability) {
      $expire = $this->now - $this->sess_expiration;

      $this->CI->db->where("last_activity < {$expire}");
      $this->CI->db->delete($this->sess_table_name);

      log_message('debug', 'Session garbage collection performed.');
    }
  }

}

// END Session Class

/* End of file Session.php */
/* Location: ./system/libraries/Session.php */